1. Draw a new layer.

2. Click on the icon for insert horizontal rule in the Common Objects Palette.

3. In the properties palette, you need to specify some settings.

W stands for width. You need to state how wide you want your line to be, in either pixels or percent.

 

H would seem like it stands for height, but it actually stands for size. A size of one is a hairline, and you can go all the way up.

 

Align is either default, left, right or center. Default means what the browser has set as a default, which could be very different than what you actually want. Make sure you set the alignment.